JP6371022B1 - Illumination method, inspection method, illumination device, and inspection device - Google Patents

Abstract

An illumination method, an inspection method, an illumination device, and an inspection device capable of improving the uniformity of the intensity of illumination light integrated over an inspection region are provided.
An illumination method according to the present invention includes a step of arranging a first ellipsoidal mirror 103 so that illumination light extracted from a light source 101 is reflected and condensed at a first condensing point IF1; A step of disposing the second ellipsoidal mirror 104 so as to reflect and collect the illumination light spreading from the first condensing point IF1 after condensing at the condensing point IF1, and in the vicinity of the first condensing point IF1. An object to be inspected by the step of disposing the light shielding member 115 for shielding the edge portions on both sides of the optical axis in the illumination light, and the illumination light condensed through the first ellipsoidal mirror 103 and the second ellipsoidal mirror 104 Illuminating 110.
[Selection] Figure 1

Description

  The present invention relates to an illumination method, an inspection method, an illumination apparatus, and an inspection apparatus. For example, illumination for detecting defects in an EUV mask used in EUV lithography (Extremely Ultraviolet Lithography) as a lithography process in a semiconductor manufacturing process. The present invention relates to a method, an inspection method, an illumination device, and an inspection device. The EUV mask to be inspected is, for example, a patterned EUV mask in which a multilayer film and an absorber are provided on a substrate (called a substrate), and the absorber is patterned.

  With regard to lithography technology for miniaturization of semiconductors, ArF lithography using an ArF excimer laser with an exposure wavelength of 193 nm as an exposure light source is currently being mass-produced. An immersion technique (called ArF immersion lithography) that fills the space between the objective lens of the exposure apparatus and the wafer with water to increase the resolution is also used for mass production. Furthermore, in order to realize further miniaturization, various technical developments have been made for practical use of EUVL with an exposure wavelength of 13.5 nm.

  As shown in FIG. 17, the EUV mask 10 is provided with a multilayer film 12 for reflecting EUV light on a substrate 11 made of low thermal expansion glass as a laminated structure. The multilayer film 12 usually has a structure in which several tens of layers of molybdenum and silicon are alternately stacked. Thereby, the multilayer film 12 can reflect about 65% of EUV light having a wavelength of 13.5 nm vertically. An absorber 13 that absorbs EUV light is provided on the multilayer film 12. Blanks can be formed by patterning the absorber 13. However, a protective film 14 (a film called a buffer layer and a capping layer) is provided between the absorber 13 and the multilayer film 12. In order to actually use for exposure, the absorber 13 is patterned by a resist process. In this way, a patterned EUV mask is completed.

  The size of an unacceptable defect in the EUV mask 10 is significantly smaller than that of a conventional ArF mask, making it difficult to detect. Accordingly, an actinic inspection that uses EUV light, that is, illumination light having the same wavelength as that of exposure light having a wavelength of 13.5 nm, is indispensable for pattern inspection. Note that the actinic inspection apparatus for blanks of the EUV mask 10 is disclosed in Non-Patent Document 1 below, for example. A light source that generates EUV light having a wavelength of 13.5 nm is sometimes referred to as an actinic light source. Here, it is referred to as an EUV light source.

  As a basic configuration of the inspection apparatus for the EUV mask 10, the EUV light extracted from the EUV light source is processed up to the EUV mask 10 by an illumination optical system including only a multilayer mirror for EUV (hereinafter simply referred to as a mirror). Then, a minute inspection area on the pattern surface of the EUV mask 10 is illuminated. The pattern of the EUV mask 10 in this inspection area is projected (imaged) onto the surface of a two-dimensional image sensor of a CCD camera or a TDI (Time Delay Integration) camera by an magnifying optical system composed only of a mirror. Then, the observed pattern is analyzed to determine whether the pattern is correct. In this way, the pattern inspection of the EUV mask 10 is performed.

  Generally, an EUV light source generates EUV light from a minute plasma. For this reason, the illumination optical system of the EUV mask inspection apparatus preferably has a configuration in which a bright spot of minute plasma is projected onto the inspection area of the EUV mask 10. However, since only a mirror can be used for the illumination optical system, for example, an optical system using one or two rotating ellipsoidal mirrors (hereinafter simply referred to as an ellipsoidal mirror) is used.

  The reason is that one ellipsoidal mirror has two focal points, and the light generated from one focal point has a property of condensing on the other focal point. As a result, the EUV light source, the ellipsoidal mirror, and the EUV mask 10 are adjusted so that one focal point is aligned with the bright spot of the plasma and the other focal point is aligned with the minute inspection region in the EUV mask 10. Deploy. Thereby, it is possible to guide and illuminate EUV light up to a minute inspection region. The EUV light source is shown in Non-Patent Documents 2 and 3 below, for example.

  The principle is the same when two ellipsoidal mirrors are used. That is, the first focal point of one of the ellipsoidal mirrors is arranged so that the bright spot of the plasma is matched, and the second focal point is arranged so that the first focal point of the other ellipsoidal mirror is matched. Further, the second focal point of the other ellipsoidal mirror is matched with the inspection area.

  On the other hand, when pattern inspection is performed by the inspection apparatus for the EUV mask 10, image data in the inspection region on the pattern surface of the EUV mask 10 is acquired using a TDI camera. The EUV mask 10 reciprocates (scans) in one direction on the stage. For this reason, the pattern surface imaged with a TDI camera always changes. Accordingly, image data is accumulated at a specific place in the pattern by the number of pulses of pulsed illumination light that repeatedly operates.

  By integrating the image data, even if there is some variation in the energy of the illumination light for each pulse, the variation in the accumulated energy is reduced. In general, when the energy variation for each pulse is X% and n pulses are integrated, the integrated energy variation becomes small as represented by the following equation (1).

  X / √ (n) (1)

  The integration of image data will be described with reference to FIG. FIG. 18 is an explanatory view showing a part of the pattern PTN of the EUV mask. The EUV mask 10 is placed on the stage. For this reason, during the inspection, the EUV mask 10 is scanned in the scan direction SC (here, from top to bottom). Therefore, the nth pulse-shaped illumination light L0 (the region indicated by an oval in the drawing) and the (n + k) th pulse-shaped illumination light L0 illuminate the minute region QN having the same pattern PTN. The micro area QN is illuminated with a total of four pulsed illumination lights L0. As a result, the projection light (light including pattern information) generated from the pattern PTN illuminated with the illumination light L0 is projected onto the TDI sensor, and therefore, the signal at a constant pixel pitch in the scanning direction of the TDI sensor. Will be accumulated.

Anna Tchikoulaeva, et.al., “EUV actinic blank inspection: from prototype to production”, Proceedings of SPIE Volume 8679, Extreme Ultraviolet (EUV) Lithography IV; 86790I (2013). Paul A. Blackborow, et.al., “EUV Source development for AIMS and Blank Inspection”, Proceedings of SPIE Volume 7636, Extreme Ultraviolet (EUV) Lithography; 763609 (2010). S. Ellwi, et.al., “High-brightness LPP source for actinic mask inspection”, Proceedings of SPIE Volume 7969, Extreme Ultraviolet (EUV) Lithography II; 79690C (2011).

  In the EUV light source developed for the inspection apparatus for the EUV mask 10, the number of repetitions of the pulse emission operation is 2 to 5 [kHz], and is about 20 [kHz] at the highest. Therefore, the number of repetitions of the pulse emission operation is low, and the accuracy of the inspection apparatus cannot be improved. The reason will be described below.

  In general, in the inspection apparatus for the EUV mask 10, the inspection area is observed at a speed of several hundred frames per second. According to this, for example, assuming that 333 frames per second, one frame is illuminated for 3.0 [ms]. That is, if the pulse light emission repetition number of the light source is 10 [kHz], 30 (10,000 × 0.003) pulses are illuminated for one frame. As a result, 30 times are accumulated for the same place in the pattern. However, strictly speaking, in the vicinity of the boundary of the inspection region, the cumulative number of pulses may be 31 pulses or 29 pulses instead of 30 pulses. Therefore, it is difficult to illuminate the entire surface of the pattern in the inspection area with uniform illuminance (integrated intensity of illumination light).

  In FIG. 18, the integration is performed for four pulses, but for the minute region QN, the first pulse and the fourth pulse are close to the end of the illumination region. Therefore, it is uncertain whether it is integrated in the inspection area set in the illumination area. If the timing of light emission of the pulse is shifted from the timing of movement by scanning the mask, the first or fourth pulse may not hit. In that case, the illumination light for 3 pulses hits the same place. Therefore, the energy accumulated so much becomes extremely low.

  An object of the present invention is to solve such problems, and an illumination method, an inspection method, and an illumination device that can improve the uniformity of the intensity of illumination light integrated over an inspection region. And providing an inspection device.

  The illumination method according to the present invention includes a step of arranging a first ellipsoidal mirror so that illumination light extracted from a light source is reflected and condensed at a first condensing point, and condensing at the first condensing point. And a step of arranging a second ellipsoidal mirror so as to reflect and collect the illumination light spreading from the first condensing point, and an optical axis of the illumination light in the vicinity of the first condensing point. Arranging a light-shielding member that shields the edge portions on both sides sandwiched; illuminating an inspection object with the illumination light condensed through the first ellipsoidal mirror and the second ellipsoidal mirror; Is provided. By setting it as such a structure, the uniformity of the intensity | strength of the illumination light integrated over a test | inspection area | region can be improved.

  Further, the inspection method according to the present invention includes a step of arranging a first ellipsoidal mirror so as to reflect the illumination light extracted from the light source and focus it on the first focus point, and at the first focus point. Disposing the second ellipsoidal mirror so as to reflect and collect the illumination light spreading from the first condensing point after condensing, and light in the illumination light in the vicinity of the first condensing point A step of arranging a light shielding member that shields end edges on both sides of the axis, and a step of illuminating the inspection object with the illumination light condensed through the first ellipsoidal mirror and the second ellipsoidal mirror And a step of condensing light from the inspection object illuminated by the illumination light, and a predetermined scan in a plane parallel to the inspection surface of the inspection object with respect to the illumination light illuminating the inspection object Focused while moving the inspection object in the direction Detecting light from the serial inspected, comprising the steps of acquiring an image of said object, and a step of inspecting said inspection target based on the image. With such a configuration, it is possible to improve the uniformity of the intensity of the illumination light integrated over the inspection region, and to inspect the inspection object with high accuracy.

  Furthermore, the illumination device according to the present invention includes a first ellipsoidal mirror that reflects the illumination light extracted from the light source and condenses the light at a first condensing point, and the first ellipsoidal mirror after condensing at the first condensing point. A second ellipsoidal mirror for reflecting and condensing the illumination light spreading from one condensing point, and an edge portion on both sides of the illumination light with an optical axis in between, arranged near the first condensing point A light shielding member that shields light, and illuminates the inspection target with the illumination light condensed through the first ellipsoidal mirror and the second ellipsoidal mirror. By setting it as such a structure, the uniformity of the intensity | strength of the illumination light integrated over a test | inspection area | region can be improved.

  The inspection apparatus according to the present invention includes a first ellipsoidal mirror that reflects the illumination light extracted from the light source and focuses the light on the first condensing point, and the first ellipsoidal mirror after condensing the first condensing point. A second ellipsoidal mirror for reflecting and condensing the illumination light spreading from one condensing point, and an edge portion on both sides of the illumination light with an optical axis in between, arranged near the first condensing point An illumination optical system that illuminates the inspection object with the illumination light collected through the first ellipsoidal mirror and the second ellipsoidal mirror, and is illuminated with the illumination light. A detection optical system that collects light from the inspection object, and the illumination light that illuminates the inspection object, the inspection object in a predetermined scan direction in a plane parallel to the inspection surface of the inspection object. While moving, the collected light from the inspection object is detected, and the inspection object And a detector for acquiring an image. With such a configuration, it is possible to improve the uniformity of the intensity of the illumination light integrated over the inspection region, and to inspect the inspection object with high accuracy.

  According to the present invention, there are provided an illumination method, an inspection method, an illumination device, and an inspection device that can improve the uniformity of the intensity of the illumination light integrated over the inspection region.

1 is a configuration diagram illustrating an inspection apparatus according to a first embodiment. In the inspection apparatus which concerns on Embodiment 1, it is the figure which illustrated the 1st condensing point vicinity. In the inspection apparatus which concerns on Embodiment 1, it is the figure which illustrated the illumination area | region of the illumination light light-shielded by the light-shielding member. It is the figure which illustrated the illumination area of the illumination light which is not shielded by the light shielding member. 5 is a flowchart illustrating an inspection method using the inspection apparatus according to the first embodiment. FIG. (A) is the figure which illustrated the pulse number which illuminates the predetermined | prescribed minute area | region in a test | inspection surface, when the illumination intensity distribution in a test | inspection area is flat, (b) shifted the timing of the start pulse which starts illumination. The horizontal axis indicates time, and the vertical axis indicates the total luminance of pulsed illumination light. (A) is the figure which illustrated the pulse number which illuminates the predetermined | prescribed minute area | region in a test | inspection surface, when the illumination intensity distribution in a test | inspection area | region is a Gaussian distribution, (b) is the timing of the start pulse which starts illumination. It is the graph which illustrated the sum total of the brightness | luminance of the micro area | region at the time of shifting, a horizontal axis shows time and a vertical axis | shaft shows the sum total of the brightness | luminance of pulse-shaped illumination light. (A) is the figure which illustrated the pulse number which illuminates the predetermined | prescribed minute area | region in an inspection surface, when the illumination intensity distribution in an inspection area | region is trapezoid, (b) is the timing of the start pulse which starts illumination It is the graph which illustrated the sum total of the brightness | luminance of the micro area | region at the time of shifting, a horizontal axis shows time and a vertical axis | shaft shows the sum total of the brightness | luminance of pulse-shaped illumination light. (A) is the figure which illustrated the pulse number which illuminates the predetermined | prescribed minute area | region in a test | inspection surface, when the illuminance distribution in a test | inspection area | region is a triangle shape, (b) is the timing of the start pulse which starts illumination. It is the graph which illustrated the sum total of the brightness | luminance of the micro area | region at the time of shifting, a horizontal axis shows time and a vertical axis | shaft shows the sum total of the brightness | luminance of pulse-shaped illumination light. It is the graph which illustrated the standard deviation of variation to fine adjustment of timing gap, a horizontal axis shows fine adjustment of timing, and a vertical axis shows standard deviation of variation. 5 is a graph illustrating by simulation a pellicle temperature of an EUV mask inspected by the inspection apparatus according to the first embodiment, where the horizontal axis indicates the illumination time and the vertical axis indicates the pellicle temperature. In the inspection apparatus which concerns on Embodiment 2, it is the figure which illustrated the 1st condensing point vicinity. In the inspection apparatus which concerns on Embodiment 2, it is the figure which illustrated the illumination area | region of the illumination light light-shielded by the light-shielding member. FIG. 6 is a configuration diagram illustrating an inspection apparatus according to a third embodiment. In the inspection apparatus which concerns on Embodiment 3, it is the figure which illustrated the illumination area | region of the illumination light light-shielded by the light shielding member. It is the figure which illustrated the illumination area of the illumination light which is not shielded by the light shielding member. It is sectional drawing which illustrated the EUV mask. It is explanatory drawing which illustrated a part of pattern of EUV mask.

  Hereinafter, a specific configuration of the present embodiment will be described with reference to the drawings. The following description shows preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. In the following description, the same reference numerals indicate substantially the same contents.

(Embodiment 1)
The inspection apparatus according to Embodiment 1 will be described with reference to the drawings. First, the configuration of the inspection apparatus will be described. Thereafter, an inspection method using the inspection apparatus will be described. FIG. 1 is a configuration diagram illustrating an inspection apparatus 100 according to the first embodiment. As illustrated in FIG. 1, the inspection apparatus 100 according to the first embodiment inspects an EUV mask pattern using, for example, an EUV mask as an inspection object 110. XYZ orthogonal coordinate axes are introduced so that the inspection surface of the inspection object 110 arranged on the stage 111 is an XY plane. The inspection apparatus 100 includes a light source 101, an illumination optical system 120, a detection optical system 130, and a detector 109.

  The light source 101 generates illumination light. The light source 101 includes, for example, a plasma 102 that generates EUV light EUV01 as illumination light. The light source 101 may be an LPP light source. The illumination light is not limited to EUV light, but may be UV light, visible light, or the like.

  The illumination optical system 120 includes a first ellipsoidal mirror 103, a second ellipsoidal mirror 104, a plane mirror 105, and a light shielding member 115. The illumination optical system 120 illuminates the inspection object 110 with illumination light collected through the first ellipsoidal mirror 103 and the second ellipsoidal mirror 104. The first ellipsoidal mirror 103 reflects the illumination light EUV01 extracted from the light source 101 and focuses it on the first focusing point IF1. The first condensing point IF1 is also referred to as a first intermediate focus. The first focal point IF1 is one of the two focal points of the first ellipsoidal mirror 103. The plasma 102 is located at the other of the two focal points of the first ellipsoidal mirror 103.

  The second ellipsoidal mirror 104 reflects and collects the illumination light EUV02 spreading from the first condensing point IF1 after condensing at the first condensing point IF1. The first condensing point IF1 is located at one of the two focal points of the second ellipsoidal mirror 104.

  The light shielding member 115 is disposed in the vicinity of the first condensing point IF1. The light shielding member 115 has, for example, a slit 116. The light shielding member 115 is disposed, for example, on the second ellipsoidal mirror 104 side with respect to the first condensing point IF between the first condensing point IF1 and the second ellipsoidal mirror 104. The light shielding member 115 may be disposed closer to the first ellipsoidal mirror 103 than the first condensing point IF between the first ellipsoidal mirror 103 and the first condensing point IF1.

  FIG. 2 is a diagram illustrating the vicinity of the first condensing point IF1 in the inspection apparatus 100 according to the first embodiment. As shown in FIG. 2, the light shielding member 115 is disposed behind the first condensing point IF1.

  Here, the rear means the detector 109 side in the optical path of light traveling from the light source 101 to the detector 109. In the optical path of light traveling from the light source 101 to the detector 109, the light source 101 side is referred to as the front.

  The light shielding member 115 has a slit 116 through which the optical axis C of the illumination light EUV02 passes. The width of the slit 116 in the direction orthogonal to the optical axis C of the illumination light EUV02 is defined as a width G1. An interval between the first condensing point IF1 and the light shielding member 115 in the optical axis C direction is defined as an interval Δf. For example, the width G1 is 18 [μm], and the interval Δf is 20 [μm]. In order to cut the outer peripheral surface of the illumination light EUV02, the width G1 depends on the NA of the illumination light EUV02 at the first condensing point IF1 and needs to be smaller than 2 · Δf · tan (asin (NA)).

  The light shielding member 115 shields part of the illumination light EUV02. The light shielding member 115 is disposed so as to slightly cut both sides of the outer peripheral surface of the conical beam with respect to the illumination light EUV02 that spreads from the first condensing point IF1. In other words, the light shielding member 115 shields the edge portions on both sides across the optical axis C of the illumination light EUV02.

  FIG. 3 is a diagram illustrating an illumination area 121 of illumination light shielded by the light shielding member 115 in the inspection apparatus 100 according to the first embodiment. FIG. 4 is a diagram illustrating an illumination area 121 of illumination light that is not shielded by the light shielding member 115. The illumination area 121 refers to an area where the inspection object 110 is illuminated by illumination light.

  As shown in FIG. 3, the light blocking member 115 blocks a part of the illumination light EUV02, so that the illuminance distribution of the illumination light on the illumination region 121 is a boundary line on the + Y axis direction side and the −Y axis direction side. Has been cut so that it is out of focus. For example, the shape of the illumination area 121 has two parallel sides facing each other. The illuminance distribution relating to the position in the Y-axis direction is such that the intensity decreases toward the + Y-axis direction side and the −Y-axis direction side. This is called inclined illumination. The slope of the illuminance, that is, the slope of the slope illumination, may be different between the + Y axis direction side and the −Y axis direction side. As described above, the light shielding member 115 is disposed in the vicinity of the first condensing point IF1 so that the illuminance distribution in the Y-axis direction has a trapezoidal shape having an inclined illumination portion. On the other hand, if the light shielding member 115 is arranged just at the first condensing point IF1 (that is, the interval Δf = 0), the boundary lines on the + Y axis direction side and the −Y axis direction side are sharp. Become.

  As shown in FIG. 4, in the case of illumination light that is not shielded by the light shielding member 115, the illumination region 121 has a round illuminance distribution with a blurred periphery. This is because the plasma 102 of the light source 101 has a spherical shape. The inspection area 131 of the inspection object 110 is, for example, 100 × 50 [μm]. Accordingly, since the inspection area 131 is smaller than the entire illumination area 121, the illumination area 121 has a substantially uniform illuminance distribution.

  3 and 4, the illumination region 121 where the inspection object 110 is illuminated by the illumination light shielded by the light shielding member 115 is disposed between the portions where the illumination light is shielded by the light shielding member 115. Further, the portions where the illumination light is shielded by the light shielding member 115 are arranged in the scanning direction. Therefore, the illumination area 121 where the inspection object 110 is illuminated by the illumination light is disposed between the portions where the illumination light is shielded by the light shielding member 115 in the scan direction.

  The plane mirror 105 reflects the illumination light EUV03 reflected and condensed by the second ellipsoidal mirror 104. The plane mirror 105 condenses the reflected illumination light EUV04 on the inspection object 110.

  The detection optical system 130 includes a Schwarzschild optical system 106, a plane mirror 107, and a concave mirror 108. The detection optical system 130 condenses the light EUV05 from the inspection object 110 illuminated by the illumination light EUV04. The illumination area 121 where the inspection object 110 is illuminated by the illumination light EUV04 covers the inspection area 131. The light EUV05 generated from the inspection object 110 in the illumination area 121 includes the reflected light and diffracted light of the illumination light EUV04. Therefore, the light EUV05 generated from the inspection object 110 includes the pattern information of the inspection region 131. The Schwarzschild optical system 106 includes a concave mirror 106a and a convex mirror 106b. The Schwarzschild optical system 106 composed of the concave mirror 106a and the convex mirror 106b is a magnifying optical system. The concave mirror 106a reflects the light EUV05 from the inspection object 110. The convex mirror 106b reflects the light EUV05 reflected by the concave mirror 106a. The plane mirror 107 and the plane mirror 108 reflect the light EUV06 reflected by the convex mirror 106b and guide it to the detector 109.

  The detector 109 is, for example, a TDI camera. When the detector 109 is a TDI camera, the inspection object 110 is moved in a predetermined scanning direction in a plane parallel to the inspection surface of the inspection object 110 with respect to the illumination light EUV04 that illuminates the inspection object 110. The light EUV05 from the object 110 is detected. The scan direction is, for example, the Y-axis direction. Then, the detector 109 acquires an image of the inspection object 110.

  The inspection object 110 is arranged on the Y direction scan table 112 in the XY stage 111. The inspection object 110 is, for example, an EUV mask, but is not limited thereto, and may be a wafer or the like. Since the inspection apparatus 100 illuminates the inspection object 110 with illumination light, it can also be called an illumination apparatus.

  Next, an inspection method will be described. FIG. 5 is a flowchart illustrating an inspection method using the inspection apparatus 100 according to the first embodiment. As shown in step S11 of FIG. 5, the first ellipsoidal mirror 103 is disposed so as to reflect the illumination light EUV01 extracted from the light source 101 and focus it on the first focus point IF.

  Next, as shown in step S12, the second ellipsoidal mirror 104 is arranged so as to reflect and collect the illumination light EUV02 spreading from the first condensing point IF1 after condensing at the first condensing point IF1. .

  Next, as shown in step S13, the light shielding member 115 is disposed in the vicinity of the first condensing point IF1. Specifically, the light shielding member 115 is disposed on the second ellipsoidal mirror 104 side with respect to the first condensing point IF1 between the first condensing point IF1 and the second ellipsoidal mirror 104. At this time, the light shielding member 115 is disposed so as to shield the edge portions on both sides of the illumination light EUV02 across the optical axis C. In addition, you may arrange | position the light shielding member 115 to the 1st ellipsoidal mirror 103 side rather than the 1st condensing point IF1 between the 1st ellipsoidal mirror 103 and the 1st condensing point IF1.

  And as shown to step S14, the test object 110 is illuminated with the illumination light EUV04 condensed through the 1st ellipsoidal mirror 103 and the 2nd ellipsoidal mirror 104. FIG.

  Specifically, the illumination light EUV01 generated from the plasma 102 of the light source 101 enters the illumination optical system 120. Then, the illumination light EUV 01 that has entered the illumination optical system 120 is reflected by the first ellipsoidal mirror 103. The illumination light EUV02 reflected by the first ellipsoidal mirror 103 travels while being narrowed down and is collected at a first condensing point IF1 (also referred to as an intermediate focus Intermediate Focus). The illumination light EUV02 once condensed at the first condensing point IF1 spreads after the first condensing point IF1. Thereafter, the illumination light EUV02 is passed through the light shielding member 115 having the slit 116. The illumination light EUV02 that has passed through the light shielding member 115 is reflected by the second ellipsoidal mirror 104. The illumination light EUV03 reflected by the second ellipsoidal mirror 104 proceeds while being narrowed down, enters the plane mirror 105, and is reflected. The illumination light EUV04 reflected by the plane mirror 105 is collected on the inspection object 110.

  Next, as shown in step S15, the light EUV05 from the inspection object 110 illuminated by the illumination light EUV04 is collected. Specifically, by illuminating the illumination light EUV04, the light EUV05 generated from the inspection object 110 is reflected by the concave mirror 106a and the convex mirror 106b. The light EUV06 reflected by the concave mirror 106a and the convex mirror 106b is folded back by the plane mirror 107 and then further expanded by the concave mirror 108. The light EUV06 magnified by the concave mirror 108 is projected onto the sensor surface disposed below the detector 109.

  Next, as shown in step S16, while the inspection object 110 is moved in the scanning direction with respect to the illumination light EUV04 that illuminates the inspection object 110, the collected light EUV06 from the inspection object 110 is detected, and the inspection is performed. An image of the object 110 is acquired. The scan direction is a predetermined direction in a plane parallel to the inspection surface of the inspection object 110, for example, the Y-axis direction. Detection of the light EUV06 from the inspection object 110 is performed by a detector 109 such as a TDI camera.

  Next, as shown in step S <b> 17, the inspection object 110 is inspected based on the image acquired by the detector 109. In this way, the inspection of the inspection object 110 is performed. Note that steps S11 to S14 can be referred to as an illumination method for illuminating illumination light EUV04 on the inspection target.

Next, the effect of this embodiment will be described.
The inspection apparatus 100 of the present embodiment forms the first focal point IF1 while guiding the illumination light EUV02 extracted from the light source 101 to the inspection object 110. In the vicinity of the first condensing point IF, the light shielding member 115 is arranged so as to linearly cut two places on the outer peripheral surface of the illumination light EUV02 that has become a conical beam. Therefore, even if the irradiation position of the illumination light EUV04 on the inspection surface of the inspection object 110 is slightly shifted for each pulse, the energy density distribution of the pulsed illumination light EUV04 integrated over the inspection region 131 is the inspection surface. It becomes almost equal regardless of the position of. This will be described below with reference to the drawings.

  FIG. 6A is an explanatory diagram illustrating the number of pulses for illuminating a predetermined minute area on the inspection surface when the illuminance distribution in the inspection area 131 is flat, and FIG. 6B is a start pulse for starting illumination. Is a graph exemplifying the total luminance of the micro area when the timing is shifted, the horizontal axis indicates the shift amount in time, and the vertical axis indicates the total luminance of the illumination light.

  As shown in FIG. 6A, the number of pulsed illumination light L0 included in the inspection region 131 indicates the integrated number of illumination light L0 that illuminates a predetermined minute region on the inspection surface. When the timing of the start pulse for starting illumination is shifted, the number of illumination lights L0 included in the inspection region 131 changes. For example, there are 30 at a certain timing and 29 at a certain timing. Therefore, the integrated number of illumination lights that illuminate the minute region also changes to 30 or 29. For example, the predetermined minute area is set to be illuminated by an average of 30 illumination lights L0. Then, the start timing shift amount is changed. Then, the number of times of entering the inspection region 131 (that is, the integrated number of the illumination light L0) may be 29 pulses due to a slight shift in the emission timing of the inspection region 131 and the illumination light L0. Therefore, the integration number changes depending on the start timing.

  As shown in FIG. 6, when the illuminance distribution in the inspection region 131 is flat, the difference in the sum of the luminances of the 29 illumination lights L0 and the 30 illumination lights L0 is the brightness of one illumination light. Will be the difference. Therefore, the standard deviation of the energy variation due to the fluctuation of the integrated number is calculated as 1.64%.

  FIG. 7A is a diagram illustrating the number of pulses that illuminate a predetermined minute region on the inspection surface when the illuminance distribution in the inspection region 131 is a Gaussian distribution, and FIG. It is the graph which illustrated the sum total of the brightness | luminance of the micro area | region in the case of.

  As shown in FIG. 7, when the illuminance distribution in the inspection region 131 is a Gaussian distribution, the difference in the sum of the luminances of the 29 illumination lights L0 and the 30 illumination lights L0 is simply one illumination. It does not make a difference in light brightness. The difference in the sum of luminance depends on the strength of the end portion with respect to the strength of the central portion of the inspection region 131. In the Gaussian distribution, the strength of the central portion of the inspection region 131 is high, and the strength is low at the end portion. Therefore, the difference in the total luminance is smaller than in the flat case. The standard deviation of the energy variation due to the fluctuation of the integrated number is calculated as 1.16%.

  FIG. 8A is a diagram illustrating the number of pulses that illuminate a predetermined minute region on the inspection surface when the illuminance distribution in the inspection region is trapezoidal, and FIG. It is the graph which illustrated the sum total of the brightness | luminance of the micro area | region in case.

  FIG. 9A is a diagram illustrating the number of pulses that illuminate a predetermined minute region on the inspection surface when the illuminance distribution in the inspection region is triangular, and FIG. 9B is a diagram in which the start pulse timing is shifted. It is the graph which illustrated the sum total of the brightness | luminance of the micro area | region in case.

  As shown in FIGS. 8 and 9, when the illuminance distribution in the inspection region 131 is trapezoidal or triangular, the illuminance distribution at the end of the inspection region 131 is inclined. In the case of the trapezoidal shape, the (W / 4) portion is inclined with respect to the length W in the Y-axis direction of the inspection region 131. As shown in FIGS. 8 and 9, the difference in the sum of the luminances of 29 illumination lights L0 and 30 illumination lights L0 is smaller than that of flat and Gaussian. The standard deviation of variation is calculated as 0.085% and 0.060%, respectively. In this embodiment, the illumination distribution can be made trapezoidal by shielding the illumination light with the light shielding member 115. Therefore, the standard deviation of the variation can be greatly reduced as compared with a flat illuminance distribution when the light shielding member 115 does not shield the light.

  FIG. 10 is a graph illustrating the standard deviation of the variation with respect to the fine adjustment of the timing deviation. The horizontal axis represents the fine adjustment of the timing, and the vertical axis represents the standard deviation of the variation. As shown in FIG. 10, for example, when the illumination light L0 is emitted such that exactly 30 pulses of illumination light L0 are included in the inspection region 131, the variation is low. The standard deviation also varies greatly depending on the amount of deviation. Even in that case, in the case of the trapezoidal illuminance distribution, the standard deviation of the variation can be reduced as compared with the flat illuminance distribution.

  As described above, according to the present embodiment, it is possible to improve the uniformity of the intensity of illumination light integrated over the inspection region 131. Therefore, the inspection object 110 can be inspected with high accuracy.

  In particular, even if the cumulative number of pulsed illumination lights is small, the inspection object 110 can be inspected with uniform sensitivity. Therefore, for example, in an EUV light source, the frequency can be set to maximize the average output without forcibly increasing the frequency. The inspection time is inversely proportional to the average output of the light source 101. Therefore, the inspection time can be shortened.

  The lifetime of the EUV light source 101 (for example, the lifetime of consumables such as electrodes) is determined by the total number of pulsed illumination lights L0 to be generated. Therefore, the lifetime of the light source 101 can be extended by setting the frequency of the illumination light to a lower value. Since the inspection apparatus of this embodiment can perform highly sensitive inspection without forcibly increasing the frequency, the lifetime of the EUV light source can be extended.

  Furthermore, when the inspection object 110 is an EUV mask with an EUV pellicle, the maximum temperature when the EUV pellicle is heated with illumination light can be lowered by several hundred degrees. The EUV pellicle is a thin film using polysilicon as a base material. Therefore, the EUV pellicle absorbs about 20% of EUV light. When illuminated with illumination light including EUV light, the temperature of the EUV pellicle rises. The temperature rise of the EUV pellicle depends on the average power of the EUV light passing through the EUV pellicle. If the average power of EUV light is high, the temperature rise is large. However, it is not proportional to linearity.

  FIG. 11 is a graph illustrating, by simulation, the pellicle temperature of the EUV mask inspected by the inspection apparatus according to the first embodiment. The horizontal axis indicates the illumination time, and the vertical axis indicates the pellicle temperature. As shown in FIG. 11, in this embodiment, a part of illumination light including EUV light is shielded by the light shielding member 115. For this reason, the power passing through the EUV pellicle is low. As a result, the temperature rise of the EUV pellicle can be suppressed. In the simulation in FIG. 11, the base material of the EUV pellicle is polysilicon having a thickness of about 45 nm. The surface is coated with ruthenium having an emissivity of 0.2. It is assumed that EUV light having an average power of about 125 mW is incident and 20% is absorbed. In the simulation, the irradiation time of EUV light is 40 milliseconds, the temperature rises with the start of irradiation, and when the temperature reaches a certain temperature, the temperature rise stops and reaches an equilibrium state. The reason why the equilibrium state is reached is that the effect of radiative cooling increases as the temperature increases. By using the light shielding member 115, the temperature in the equilibrium state can be lowered by about 400 degrees as compared with the case where the light shielding member 115 is not used.

  Thus, the reason why the temperature increase of the EUV pellicle can be suppressed is as follows. That is, the illumination light irradiation area on the EUV pellicle surface has almost the same size regardless of the presence or absence of the light shielding member 115. Therefore, the intensity of the illumination light can be reduced by arranging the light shielding member 115. The illuminance distribution of the illumination light varies as shown in FIGS. 3 and 4 depending on the presence or absence of the light shielding member 115 on the EUV mask surface. However, the EUV pellicle surface is 2 mm away from the pattern surface of the EUV mask. Therefore, since the EUV pellicle surface does not become a common position with the first condensing point IF1, it is illuminated with substantially the same round shape regardless of the presence or absence of the light shielding member 115, so that an increase in temperature can be suppressed.

(Embodiment 2)
Next, Embodiment 2 will be described. The inspection apparatus according to the second embodiment is different from the inspection apparatus 1 according to the first embodiment in the configuration of the light shielding member 215. FIG. 12 is a diagram illustrating the vicinity of the first condensing point IF1 in the inspection apparatus according to the second embodiment.

  As shown in FIG. 12, the light shielding member 215 includes one light shielding plate 215a and the other light shielding plate 215b. One light shielding plate 215a and the other light shielding plate 215b are arranged in the vicinity of the first light condensing point IF1. One light shielding plate 215a is disposed closer to the first ellipsoidal mirror 103 than the first focusing point IF between the first ellipsoidal mirror 103 and the first focusing point IF1. The other light shielding plate 215 b is disposed on the second ellipsoidal mirror 104 side with respect to the first condensing point IF1 between the first condensing point IF1 and the second ellipsoidal mirror 104.

  A distance between one light shielding plate 215a and the other light shielding plate 215b in a direction orthogonal to the optical axis C of EUV02 is defined as a distance G2. An interval between the first condensing point IF1 and each light shielding plate in the direction of the optical axis C is defined as an interval Δf. For example, the interval G2 is 22 [μm], and the interval Δf is 25 [μm]. In order to cut the outer peripheral surface of the illumination light EUV02, the interval G2 depends on the NA of the illumination light EUV02 at the first condensing point IF1 and needs to be smaller than 2 · Δf · tan (asin (NA)).

  One light shielding plate 215a and the other light shielding plate 215b shield part of the illumination light EUV02. One light-shielding plate 215a and the other light-shielding plate 215b are arranged so as to slightly cut both sides of the outer peripheral surface of the conical beam with respect to the illumination light EUV02 that spreads from the first condensing point IF1. In other words, the light shielding member 215 including one light shielding plate 215a and the other light shielding plate 215b shields the edge portions on both sides across the optical axis C of the illumination light EUV02.

  FIG. 13 is a diagram illustrating the illumination area 121 of the illumination light EUV04 shielded by the light shielding member 215 in the inspection apparatus according to the second embodiment. As shown in FIG. 13, the one light shielding plate 215a and the other light shielding plate 215b shield part of the illumination light EUV02, so that the illuminance distribution of the illumination light EUV04 on the illumination region 121 is on the + Y axis direction side. And it is cut so that the boundary line on the −Y axis direction side is out of focus. For example, the shape of the illumination area 121 has two parallel sides facing each other. The illuminance distribution is inclined illumination in which the intensity decreases toward the + Y axis direction side and the −Y axis direction side. When light is shielded by the light shielding member 215, unlike in the case of light shielding by the light shielding member 115, the illuminance gradients on the + Y axis direction side and the −Y axis direction side can be made equal. Therefore, it is possible to suppress the light amount loss more than the light shielding member 115. As described above, one light shielding plate 215a and the other light shielding plate 215b of the light shielding member 215 are arranged in the vicinity of the first condensing point IF1 so that the illuminance distribution in the Y-axis direction has a trapezoidal shape having an inclined illumination portion. Is done. Further, the illuminance gradients on the + Y axis direction side and the −Y axis direction side are arranged to be equal.

  One reason why the slope of one side in the inclined illumination becomes gentle is that the first condensing point IF1 in the vicinity of the light shielding member 115 is projected onto the inspection object 110 by only one ellipsoidal mirror 104. In one second ellipsoidal mirror 104, the illumination light EUV02 is bent at about 90 degrees, so the profile of the illumination light EUV02 in the vicinity of the light shielding member 115 and the first condensing point IF1 and the illumination light immediately before the inspection object 110 are obtained. This is probably because the EUV04 profile is not completely covered. Other configurations and effects are included in the description of the first embodiment.

(Embodiment 3)
Next, Embodiment 3 will be described. In the present embodiment, the light source is an LPP light source. In addition, the present embodiment includes a third ellipsoidal mirror. FIG. 14 is a configuration diagram illustrating an inspection apparatus according to the third embodiment.

  As illustrated in FIG. 14, the inspection apparatus 300 according to the third embodiment includes a light source 310, an illumination optical system 320, a detection optical system 330, and a detector 309.

  The light source 310 is, for example, an LPP light source. The light source 310 generates illumination light EUV300 including, for example, EUV light. The light source 310 includes a tin supply tank 301, a recovery container 303, and a lens 304.

  In the light source 310, the tin drop 302 is blown from the tin supply tank 301 at high speed. Laser light L300 emitted from a near-infrared laser device (not shown) is condensed on the tin drop 302 via the lens 304. Thereby, tin plasma is generated. Therefore, illumination light EUV300 is generated from the plasma. The tin drop 302 that has not been irradiated with the laser beam L300 and has not generated plasma is recovered and stored in the recovery container 303.

  The illumination optical system 320 includes a first ellipsoidal mirror 321, a second ellipsoidal mirror 322, a third ellipsoidal mirror 323, a plane mirror 324, and a light shielding member 315. The first ellipsoidal mirror 321 is sometimes called a collector mirror. The illumination light EUV 300 generated from the plasma in the tin drop 302 is reflected by the first ellipsoidal mirror 321. The illumination light EUV301 reflected by the first ellipsoidal mirror 321 proceeds while being narrowed down and is condensed at the first condensing point IF1. The illumination light EUV301 once condensed at the first condensing point IF1 spreads after the first condensing point IF1. Thereafter, the illumination light EUV 301 passes through the light shielding member 315.

  The light shielding member 315 is disposed on the second ellipsoidal mirror 211 side with respect to the first condensing point IF1 between the first condensing point IF1 and the second ellipsoidal mirror 211. The light shielding member 315 may be disposed closer to the first ellipsoidal mirror 321 than the first condensing point IF1 between the first ellipsoidal mirror 321 and the first condensing point IF1. The light shielding member 315 has a slit through which the optical axis of the illumination light EUV301 passes. Thereby, the light shielding member 315 shields the edge portions on both sides across the optical axis of the illumination light EUV301. For example, the width G of the slit is 50 [μm], and the interval Δf between the first condensing point IF1 and the light shielding member 315 is 50 [μm]. In order to cut the outer peripheral surface of the illumination light EUV301, the width G depends on the NA of the illumination light EUV301 at the first condensing point IF1 and needs to be smaller than 2 · Δf · tan (asin (NA)).

  The illumination light EUV 301 that has passed through the light shielding member 315 is reflected by the second ellipsoidal mirror 322. The illumination light EUV302 reflected by the second ellipsoidal mirror 322 proceeds while being narrowed down and is condensed at the second condensing point IF2. The illumination light EUV302 once condensed at the second condensing point IF2 spreads after the second condensing point IF2. Thereafter, the illumination light EUV 302 is reflected by the third ellipsoidal mirror 323. The illumination light EUV 303 reflected by the third ellipsoidal mirror 323 proceeds while being narrowed down, enters the plane mirror 324, and is reflected. The illumination light EUV 304 reflected by the plane mirror 324 is collected on the inspection object 110.

  As described above, the illumination optical system 320 reflects the illumination light EUV302 spreading from the second condensing point IF2 after the second condensing point IF2 where the illumination light EUV302 is condensed by the second ellipsoidal mirror 322. A third ellipsoidal mirror 323 for collecting light is further provided. The illumination optical system 320 illuminates the inspection object 110 with the illumination light EUV 304 collected via the first ellipsoidal mirror 321, the second ellipsoidal mirror 322, and the third ellipsoidal mirror 323. Configurations of the detection optical system 330, the detector 309, and the like are the same as those in the first embodiment. The inspection method using the inspection apparatus 300 reflects the illumination light EUV302 that spreads from the second condensing point IF2 after the second condensing point IF2 where the illumination light EUV302 is condensed by the second ellipsoidal mirror 322. Except for disposing the third ellipsoidal mirror 323 so as to collect light, it is the same as the inspection method of the first embodiment.

  FIG. 15 is a diagram illustrating the illumination area 121 of the illumination light EUV 304 shielded by the light shielding member 315 in the inspection apparatus 300 according to the third embodiment. As shown in FIG. 15, the light shielding member 315 shields a part of the illumination light EUV301, so that the illuminance distribution of the illumination light EUV304 on the illumination region 121 is a boundary between the + Y axis direction side and the −Y axis direction side. The lines are cut so that they are out of focus. For example, the shape of the illumination area 121 has two parallel sides facing each other. The illuminance distribution is inclined illumination in which the intensity decreases toward the + Y axis direction side and the −Y axis direction side. As described above, the light shielding member 315 is disposed in the vicinity of the first condensing point IF1 so that the illuminance distribution in the Y-axis direction has a trapezoidal shape having an inclined illumination portion. When light is shielded by the light shielding member 315, unlike the case where light is shielded by the light shielding member 115, the illuminance gradients on the + Y axis direction side and the −Y axis direction side can be made equal. Therefore, it is possible to suppress the light amount loss more than the light shielding member 115.

  FIG. 16 is a diagram illustrating an illumination area of the illumination light EUV 304 that is not shielded by the light shielding member 315. As shown in FIG. 16, in the case of the illumination light EUV304 that is not shielded by the light shielding member 315, the illumination region 121 has a round illuminance distribution with a blurred periphery.

  15 and FIG. 16, the illumination region 121 in which the inspection object 110 is illuminated by the illumination light EUV 304 shielded by the light shielding member 315 is disposed between the portions where the illumination light EUV 301 is shielded by the light shielding member 115. . Further, the portions where the illumination light EUV301 is shielded by the light shielding member 315 are arranged in the scanning direction. Therefore, the illumination area 121 where the inspection object 110 is illuminated by the illumination light EUV 304 is disposed between the portions where the illumination light EUV 301 is shielded by the light shielding member 115 in the scan direction.

  The inspection apparatus 300 according to the present embodiment has two condensing points. A light shielding member 315 is arranged in the vicinity of the second first condensing point IF1 from the inspection object 110 side among the two condensing points. Thereby, illumination intensity distribution can be made trapezoidal and the magnitude | size of the slope of two inclined illuminations can be made equivalent. When the illumination light EUV02 shielded by the light shielding member 115 is projected by only one ellipsoidal mirror as in the first embodiment, a difference occurs in the slopes of the two inclined illuminations having the illuminance distribution. However, in this embodiment, the illumination light EUV 201 shielded by the light shielding member 315 is relayed to the inspection object 110 using two ellipsoidal mirrors. Moreover, two elliptical mirrors are used in opposite directions. By doing in this way, the slopes of two inclined illuminations with illuminance distribution can be made equal.

  As mentioned above, although embodiment of this invention was described, this invention contains the appropriate deformation | transformation which does not impair the objective and advantage, Furthermore, it does not receive the restriction | limiting by said embodiment.

DESCRIPTION OF SYMBOLS 10 EUV mask 11 Substrate 12 Multilayer film 13 Absorber 14 Protective film 100, 300 Inspection apparatus 101, 310 Light source 102 Plasma 103, 321 First ellipsoidal mirror 104, 322 Second ellipsoidal mirror 105, 107 Planar mirror 106 Schwarzschild optical system 106a Concave mirror 106b Convex mirror 108 Concave mirror 109 Detector 110 Inspection object 111 XY stage 112 Y direction scan table 115, 315 Light blocking member 116 Slit 120, 320 Illumination optical system 121 Illumination area 130, 330 Detection optical system 131 Inspection area 301 Tin supply tank 302 Tin drop 303 Recovery container 304 Lens 323 Third ellipsoidal mirror 324 Plane mirror IF1 First focusing point IF2 Second focusing point EUV01, EUV02, EUV03, EUV04 Illumination light EUV300, EUV301, EUV 302, EUV303, EUV304 Illumination light EUV05, EUV06 Light PTN pattern L0 Illumination light SC Scan direction

Claims (14)

Disposing the first ellipsoidal mirror so as to reflect the illumination light extracted from the light source and focus it on the first focusing point;
Disposing a second ellipsoidal mirror to reflect and collect the illumination light spreading from the first condensing point after condensing at the first condensing point;
Arranging a light shielding member that shields the edge portions on both sides sandwiching the optical axis of the illumination light in the vicinity of the first condensing point;
Illuminating the inspection object with the illumination light condensed through the first ellipsoidal mirror and the second ellipsoidal mirror;
Equipped with a,
The light shielding member includes one light shielding plate and the other light shielding plate,
In the step of arranging the light shielding member,
The one light shielding plate is disposed closer to the first ellipsoidal mirror than the first condensing point between the first ellipsoidal mirror and the first condensing point,
The other light-shielding plate is an illumination method arranged on the second ellipsoidal mirror side with respect to the first condensing point between the first condensing point and the second ellipsoidal mirror . Disposing the first ellipsoidal mirror so as to reflect the illumination light extracted from the light source and focus it on the first focusing point;
Disposing a second ellipsoidal mirror to reflect and collect the illumination light spreading from the first condensing point after condensing at the first condensing point;
A third ellipsoidal mirror is arranged to reflect and collect the illumination light spreading from the second condensing point after the second condensing point where the illumination light is collected by the second ellipsoidal mirror. Placing step;
Arranging a light shielding member that shields the edge portions on both sides sandwiching the optical axis of the illumination light in the vicinity of the first condensing point;
Illuminating the inspection object with the illumination light condensed through the first ellipsoidal mirror , the second ellipsoidal mirror, and the third ellipsoidal mirror ;
Equipped with a,
The said light shielding member is an illumination method which has a slit through which the optical axis of the said illumination light passes . The light source is an LPP light source.
A method as claimed in claim 1 or 2. The illumination area where the inspection object is illuminated by the illumination light is disposed between portions where the illumination light is shielded by the light shielding member,
The illumination method according to any one of claims 1 to 3 . Disposing the first ellipsoidal mirror so as to reflect the illumination light extracted from the light source and focus it on the first focusing point;
Disposing a second ellipsoidal mirror to reflect and collect the illumination light spreading from the first condensing point after condensing at the first condensing point;
Arranging a light shielding member that shields the edge portions on both sides sandwiching the optical axis of the illumination light in the vicinity of the first condensing point;
Illuminating the inspection object with the illumination light condensed through the first ellipsoidal mirror and the second ellipsoidal mirror;
Condensing light from the inspection object illuminated by the illumination light;
With respect to the illumination light that illuminates the inspection object, the condensed light from the inspection object is detected while moving the inspection object in a predetermined scanning direction in a plane parallel to the inspection surface of the inspection object. And obtaining an image of the inspection object;
Inspecting the inspection object based on the image;
Equipped with a,
The light shielding member includes one light shielding plate and the other light shielding plate,
In the step of arranging the light shielding member,
The one light shielding plate is disposed closer to the first ellipsoidal mirror than the first condensing point between the first ellipsoidal mirror and the first condensing point,
The other light-shielding plate is an inspection method arranged on the second ellipsoidal mirror side with respect to the first condensing point between the first condensing point and the second ellipsoidal mirror . Disposing the first ellipsoidal mirror so as to reflect the illumination light extracted from the light source and focus it on the first focusing point;
Disposing a second ellipsoidal mirror to reflect and collect the illumination light spreading from the first condensing point after condensing at the first condensing point;
A third ellipsoidal mirror is arranged to reflect and collect the illumination light spreading from the second condensing point after the second condensing point where the illumination light is collected by the second ellipsoidal mirror. Placing step;
Arranging a light shielding member that shields the edge portions on both sides sandwiching the optical axis of the illumination light in the vicinity of the first condensing point;
Illuminating the inspection object with the illumination light condensed through the first ellipsoidal mirror , the second ellipsoidal mirror, and the third ellipsoidal mirror ;
Condensing light from the inspection object illuminated by the illumination light;
With respect to the illumination light that illuminates the inspection object, the condensed light from the inspection object is detected while moving the inspection object in a predetermined scanning direction in a plane parallel to the inspection surface of the inspection object. And obtaining an image of the inspection object;
Inspecting the inspection object based on the image;
Equipped with a,
The said light shielding member is an inspection method which has a slit through which the optical axis of the said illumination light passes . The illumination area in which the inspection object is illuminated by the illumination light is disposed between portions where the illumination light is shielded by the light shielding member in the scanning direction.
The inspection method according to claim 5 or 6 . A first ellipsoidal mirror for reflecting the illumination light extracted from the light source and condensing it at the first condensing point;
A second ellipsoidal mirror for reflecting and condensing the illumination light spreading from the first condensing point after condensing at the first condensing point;
A light-shielding member that is disposed in the vicinity of the first condensing point and shields edge portions on both sides across the optical axis of the illumination light;
With
An illumination device that illuminates an inspection object with the illumination light condensed through the first ellipsoidal mirror and the second ellipsoidal mirror ,
The light shielding member includes one light shielding plate and the other light shielding plate,
The one light shielding plate is disposed closer to the first ellipsoidal mirror than the first condensing point between the first ellipsoidal mirror and the first condensing point,
The other light-shielding plate is an illuminating device disposed on the second ellipsoidal mirror side with respect to the first condensing point between the first condensing point and the second ellipsoidal mirror . A first ellipsoidal mirror for reflecting the illumination light extracted from the light source and condensing it at the first condensing point;
A second ellipsoidal mirror for reflecting and condensing the illumination light spreading from the first condensing point after condensing at the first condensing point;
A third ellipsoidal mirror for reflecting and condensing the illumination light spreading from the second condensing point after the second condensing point on which the illumination light is collected by the second ellipsoidal mirror;
A light-shielding member that is disposed in the vicinity of the first condensing point and shields edge portions on both sides across the optical axis of the illumination light;
With
An illumination device that illuminates an inspection object with the illumination light condensed through the first ellipsoidal mirror , the second ellipsoidal mirror, and the third ellipsoidal mirror ,
The said light shielding member is an illuminating device which has a slit through which the optical axis of the said illumination light passes . The light source is an LPP light source.
The lighting device according to claim 8 or 9 . The illumination area where the inspection object is illuminated by the illumination light is disposed between portions where the illumination light is shielded by the light shielding member,
The lighting device according to any one of claims 8 to 10 . A first ellipsoidal mirror for reflecting the illumination light extracted from the light source and condensing it at the first condensing point;
A second ellipsoidal mirror for reflecting and condensing the illumination light spreading from the first condensing point after condensing at the first condensing point;
A light-shielding member that is disposed in the vicinity of the first condensing point and shields edge portions on both sides across the optical axis of the illumination light;
An illumination optical system that illuminates the inspection object with the illumination light condensed through the first ellipsoidal mirror and the second ellipsoidal mirror, and
A detection optical system that collects light from the inspection object illuminated by the illumination light;
With respect to the illumination light that illuminates the inspection object, the condensed light from the inspection object is detected while moving the inspection object in a predetermined scanning direction in a plane parallel to the inspection surface of the inspection object. And a detector for acquiring an image of the inspection object,
Equipped with a,
The light shielding member includes one light shielding plate and the other light shielding plate,
The one light shielding plate is disposed closer to the first ellipsoidal mirror than the first condensing point between the first ellipsoidal mirror and the first condensing point,
The other light-shielding plate is an inspection apparatus disposed on the second ellipsoidal mirror side with respect to the first condensing point between the first condensing point and the second ellipsoidal mirror. A first ellipsoidal mirror for reflecting the illumination light extracted from the light source and condensing it at the first condensing point;
A second ellipsoidal mirror for reflecting and condensing the illumination light spreading from the first condensing point after condensing at the first condensing point;
A third ellipsoidal mirror for reflecting and condensing the illumination light spreading from the second condensing point after the second condensing point on which the illumination light is collected by the second ellipsoidal mirror;
A light-shielding member that is disposed in the vicinity of the first condensing point and shields edge portions on both sides across the optical axis of the illumination light;
An illumination optical system that illuminates the inspection object with the illumination light condensed through the first ellipsoidal mirror , the second ellipsoidal mirror, and the third ellipsoidal mirror , and
A detection optical system that collects light from the inspection object illuminated by the illumination light;
With respect to the illumination light that illuminates the inspection object, the condensed light from the inspection object is detected while moving the inspection object in a predetermined scanning direction in a plane parallel to the inspection surface of the inspection object. And a detector for acquiring an image of the inspection object,
Equipped with a,
The light shielding member is an inspection apparatus having a slit through which an optical axis of the illumination light passes . The illumination area in which the inspection object is illuminated by the illumination light is disposed between portions where the illumination light is shielded by the light shielding member in the scanning direction.
The inspection apparatus according to claim 12 or 13 .